properscalarincreasingconvexfunction.hh

/* -*- mode:c++; mode:semantic -*- */

#ifndef PROPER_SCALAR_INCREASING_CONVEX_FUNCTION_HH
#define PROPER_SCALAR_INCREASING_CONVEX_FUNCTION_HH

class ProperScalarIncreasingConvexFunction {
public:
  virtual double operator()(const double s) const = 0;
  virtual double leftDifferential(const double s) const = 0;
  virtual double rightDifferential(const double s) const = 0;
};

class SampleFunction : public ProperScalarIncreasingConvexFunction {
public:
  double operator()(const double s) const { return (s < 1) ? s : (2 * s - 1); }

  double leftDifferential(const double s) const { return (s <= 1) ? 1 : 2; }

  double rightDifferential(const double s) const { return (s < 1) ? 1 : 2; }
};

class TrivialFunction : public ProperScalarIncreasingConvexFunction {
public:
  double operator()(const double) const { return 0; }

  double leftDifferential(const double) const { return 0; }

  double rightDifferential(const double) const { return 0; }
};

#endif